Electric steam bath stove



p 3, 1968 E. ISOMAA 3,400,248

ELECTRIC STEAM BATH STOVE Filed Feb. 7. 1966 3 Sheets-Sheet l FIG. 1

pt. 3, 1968 E. ISOMAA 3,400,248

ELECTRIC STEAM BATH STOVE Filed Feb. 7. 1966 3 Sheets-Sheet 2 Sept. 3,1968 E. ISOMAA ELECTRIC STEAM BATH STOVE 3 Sheets-Sheet 3 Filed Feb. '7.1966 FIG. 3

FIG.4

mvsmox ISOMAA ERIK ,4 A ORNEYS United States Patent 3,400,248 ELECTRICSTEAM BATH STOVE Erik Isomaa, Kadetintie 9, Munkkiniemi, Helsinki,Finland Filed Feb. 7, 1966, Ser. No. 525,471 Claims priority,application Finland, Dec. 8, 1965,

2,950/ 65 6 Claims. (Cl. 219-367) ABSTRACT OF THE DISCLOSUREThermostatically controlled heating elements are positioned in the innerjacket of a sauna stove below the perforated bottom of an open-toppedstove-filled compartment at the upper end of the jacket. An outer jacketsurrounds the inner jacket and compartment to define a passage throughwhich room air flows thereby maintaining the temperature of the outerjacket at a safe level. Room air also flows upwardly through the innerjacket over the elements and through the stove compartment. Some of theheated air from the inner jacket is diverted into the upper end of thepassage to accelerate the flow of room air therethrough.

The present invention relates to an electric steam bath stove of the socalled Finnish sauna-oven type comprising at the top an open compartmentfilled with stones, which are arranged to be heated by the aid of anelectric heating unit so as to when water is poured on the hot stonesthey create steam. The invention relates particularly to stoves havingmultiple jackets. Said stoves contain canals, adapted to conduct airupwards from the floor level under simultaneous heating of the air. Theheated air is used for the heating of the bath room itself, whilst thesteam from the hot stones serve the steam bathing purposes.

Previously known stoves of this type have a number of disadvantages. Ithas not been possible to arrange an efiicient and fast working heatingdevice with such a stone volume which is big enough to give the desiredheating capacity for the stones to create steam. The air stream flowingupwards from the floor level in known double jackets sauna ovens doesnot provide enough warm air for an effective heating of the bathroom.The balance between sufficiently heated stones and a sufficient quantityof heated air for the bathroom has been inadequate.

According to one known stove construction the air rising in the doublejacket flows into the stone compartment through holes in the innerjacket. Before this air comes out into the bath room, it mustconsequently pass at least a part of the stones in the stonecompartment. This causes an unwanted cooling of the stones. Anotherdisadvantage in known stove types that the shape and dimensions of thejackets are ill suited for economical treatment in for instanceenamelling, anodizing and chrome units.

In the stove according to the present invention these disadvantages havebeen eliminated. Its jacket is composed of elements suitably dimensionedfor economical and practical finishing treatment. The shape of the stovediffers from that of previously known electric stoves by the fact thatit is shaped as a cylinder. Its double jacket is constructed as to leadthe air rising in the jacket space out into the bath room in anextremely eflicient manner and which will not affect the heating of thestones. The temperature of the outer jacket of the stove is neverthelessmaintained at a level which cannot do any harm to the bather in the bathroom.

The electric steam bath stove according to the present invention is ingeneral characterized in that it is of cylindrical shape and that itsouter jacket is horizontally, for instance halfway up divided into twodifferent parts, whereby the uppper jacket part has a larger diameterthan the lower jacket part, and protrudes telescopically over the edgeof the lower jacket, forming an annular space between the jacket parts,through which additional air from the outside can enter and join the airflow rising in conventional manner from the floor level up between theinner and outer jackets and that the double jacket of the stove at thetop has an annular top piece, which closes the space between the jacketsand has a conical, inwardly including outer wall provided with oblongslots all round the periphery through which the air rising in the jacketspace is conducted obliquely upwards and out into the bath room.

The outer wall of the annular top piece may according to anotherembodiment of the stove be vertical and have guiding planes on theinside conducting the air in outward and upward direction.

According to another embodiment may the stove at the top, near the stonecompartment have a third jacket wall, which is so arranged as to conducta part of the hot air flowing through the electrical heating unit alongthe outside surface of the wall of the stone compartment, whereupon itjoins the air rising up in the double jacket. This latter air flow isthereby accelerated through the additional overheated air and flows withgreater speed out into the bath room.

The invention will now be described in detail with reference to theaccompanying drawing, visualizing one suitable embodiment thereof.

FIG. 1 shows the stove from the side and partly in vertical section,

FIG. 2 shows the stove seen from above and partly in horizontal sectionalong the line 22 in FIG. 1,

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2, and

FIG. 4 is a view similar to FIG. 3, but showing an alternate embodimentof the present invention.

The jacket of the stove is composed of two parts 1 and 2, whichapproximately halfway up the stove are telescopically overlapping eachother as to create opening 3 between them, through which air can flowinto the space between the outer jacket, composed of parts 1 and 2, andthe inner jacket 4. At the base of the stove air comes from the floorlevel through the opening 5 in between the inner jacket 4 and the lowerpart 2 of the outer jacket. The air flowing in through the opening 5later joins the additional air coming in through the opening 3 andcontinues upwards into an annular top piece 6, which closes the spacebetween the outer and inner jackets of the stove. The top piece has aninwards conically inclining wall 6 with oblong slots 7. The rising airis conducted obliquely upwards and outwards through said slots 7. Thestone compartment of the stove is indicated by reference 8. Its bottom 9is perforated, having holes 9' for heating air coming from the heatingunit arranged beneath the stone compartment. The electric heating unitcomprises two groups of electrical elements 10 and 10 and is supportedby a flange part 11 under the bottom 9 of the stone compartment. Theheating unit is regulated by a thermostat switching one or both elementgroups off when desired temperature is reached. The lower group ispreferably shut off first. The upper group, which serves to heat thestones, is not shut off until the stones are sufficiently hot. Thestones are designated 8'. Under the heating unit is a valve device 12,by which the flow of air, which passes the stones heating them, can beregulated. The valve 12 will also protect the floor under the stoveagainst overheating. The stove stands on an elongation of the innerjacket 4, which has been provided with holes 13 for the air entering theheating unit. At the side of the stove there is a box 14 for electriccurrent leading-ins, fuses etc.

The upper part of jacket 4"is bent inward as shown at 4a, but does notextend to stone compartment 8. Also, there is a vertical opening 15 inthe inner jacket 4 for inserting of the heating unit, including plate17, from above into the stove. An annular canal 16 from the heating unitspace is formed between the stone compartment 8 and the upper part ofthe inner jacket 4, which canal is adapted to conduct heated air fromthe heating unit to flow out and along the outer surface of the stonecompartment 8 and then to join the air rising in the space in the doublejacket and to disappear through the slots 7 in the annular top piece.Due to the perforated bottom of the stone container, the regulatingvalve 12 and the side heating of the container by air coming through theslot 16, the stone compartment can be enlarged in comparison withpreviously known stove types so that the stone volume correspondsapproximately to at least two thirds of the volume of the space occupiedby the heating unit. Thus the heating capacity of the stove is improved.

FIG. 4 depicts an alternative embodiment of the present invention inwhich the top piece 6 has a cylindrical outer wall 6a having a pluralityof spaced slots 7a. Associated with slots 7a and extending downwardlyand inwardly from the tops thereof are louvres 20 which serve to guidethe heated air out through said slots 7a.

Other modifications of the details of the stove can of course be madewithin the scope of the invention. According to one modified embodimentthe slots in the top piece are adjustable for regulating the amount ofair escaping through the slots 7. According to still another embodimentvalves are provided to regulate the amount of air passing between thejackets of the stove and through the heating unit.

What I claim is:

1. An electrical steam bath stove of the sauna-oven type comprising aninner jacket; an outer jacket telescoped over said inner jacket andspaced therefrom to define an air flow passage between said jackets; astone compartment disposed in the upper portion of said inner jacket,said stone compartment having an open top providing an air outlet, and aperforated bottom plate; heat- Cil ing means disposedwithin said innerjacket and below said stone compartment, an annular top piece extendingfrom said stone compartment to said outer jacket and covering said airflow passage; and an air inlet into the lower portion of the innerjacket so that air may fiow upwardly through said inner jacket, oversaid heating unit, through said bottom plate and stones, and out saidtop of said compartment.

2. The stove of claim 1, wherein said top piece has an outer wallinclined conically upwardly and inwardly, a plurality of verticallyoblong slots being formed in the periphery of said wall to provide anair outlet for said air flow passage.

3. The stove of claim 1, wherein said top piece has at least onecylindrical vertical wall with oblong slots being formed thereon toprovide an outlet for said air flow passage, and further comprisingguiding means provided on the inside of said slots and adapted toconduct the air flowing through said air fiow passage upwardly andoutwardly.

4. The stove of claim 1, wherein said stone compartment has a volumeapproximately corresponding to at least two-thirds of the volume of thespace occupied by said heating means.

5. The stove of claim 1, further comprising regulating means disposed insaid inner jacket and adapted to regulate the flow of air therethrough.

6. The stove of claim 1, wherein the side wall of said stone compartmentis spaced from the inner surface of said inner jacket to define anadditional air flow passage.

References Cited UNITED STATES PATENTS 2,709,214 5/ 1955 Engdahl.

3,275,800 9/1966 Kuoppamaki et a1. 219378 X 3,299,443 1/1967 Ketola219-378 X FOREIGN PATENTS 208,996 5/ 1960 Austria. 654,810 12/1962Canada.

ANTHONY BARTIS, Primary Examiner.

